Joseph R Dettori

Avoiding wrong site surgery: a systematic review.

Study Design. Systematic review. Objective. To report the incidence and causes of wrong site surgery and determine what preoperative measures are effective in preventing wrong site surgery. Summary of Background Data. From 1995 to 2005, the Joint Commission (JC) sentinel event statistics database ranked wrong site surgery as the second most frequently reported event with 455 of 3548 sentinel events (12.8%). Although the event seems to be rare, the incidence of these complications has been difficult to measure and quantify. The implications for wrong site surgery go beyond the effects to the patient. Such an event has profound medical, legal, social, and emotional implications. Methods. A systematic review of the English language literature was undertaken for articles published between 1990 and December 2008. Electronic databases and reference lists of key articles were searched to identify the articles defining wrong site surgery and reporting wrong site events. Two independent reviewers assessed the level of evidence quality using the Grading of Recommendations Assessment, Development, and Evaluation criteria and disagreements were resolved by consensus. Results. The estimated rate of wrong site surgery varies widely ranging from 0.09 to 4.5 per 10,000 surgeries performed. There is no literature to substantiate the effectiveness of the current JC Universal Protocol in decreasing the rate of wrong site, wrong level surgery. Conclusion. Wrong site surgery may be preventable. We suggest that the North American Spine Society and JC checklists are insufficient on their own to minimize this complication. Therefore, in addition to these protocols, we recommend intraoperative imaging after exposureand marking of a fixed anatomic structure. This imaging should be compared with routine preoperative studies to determine the correct site for spine surgery.

The influence of perioperative risk factors and therapeutic interventions on infection rates after spine surgery: a systematic review.

Study Design. Systematic review. Objective. The objectives of this systematic review were to determine the patient and perioperative risk factors that contribute to infections after spine surgery and to examine the level of evidence to support the use of therapeutic interventions to reduce infection rates. Summary of Background Data. Infection continues to be one of the most common and feared complications after spine surgery. As such, it is used as a sentinel event for quality assurance processes. It is clear that the causes of infections after spine surgery are multifactorial and numerous patient- and procedure-related factors have been proposed as contributory elements. In addition, numerous perioperative adjuncts have been suggested to reduce infection rates. Methods. A systematic review of the English-language literature (published between January 1990 and June 2009) was undertaken to identify articles examining risk factors associated with and adjunct treatment measures for preventing surgical-site infections. Two independent reviewers assessed the level of evidence quality using the Grading of Recommendations Assessment, Development, and Evaluation criteria, and disagreements were resolved by consensus. Results. Of the 127 articles identified, 32 met the criteria to undergo full-text review. Individual patient, operative, and perioperative variables have been identified that are associated with increased infection rates (i.e., older age, obesity, diabetes, malnutrition, higher American Society of Anesthesiologists score, posterior approaches, and blood transfusions) but these variables have not been combined to provide individual patient risks based on a composite of factors (e.g., risk stratification). Of the surgical adjuncts investigated, only irrigation with dilute betadine solution showed moderate support for reducing infection rates. Conclusion. It is clear that the causes of postoperative spinal site infections are multifactorial and related to a complex interplay of patient and procedural influences. Because of these complexities, for any individual and surgical procedure, predictable infection rates likely exist that do not extrapolate to 0. Although we have identified factors associated with increased infection rates, further studies will be required to allow multifactorial risk stratification for individual patients and to further investigate the use of therapeutic adjuncts.

Chronic low back pain: A heterogeneous condition with challenges for an evidence-based approach

“Chronic” low back pain (LBP), defined as present for 3 or more months, has become a major socioeconomic problem insufficiently addressed by five major entities largely working in isolation from one another – procedural based specialties, strength based rehabilitation, cognitive behavioral therapy, pain management and manipulative care. As direct and indirect costs continue to rise, many authors have systematically evaluated the body of evidence in an effort to demonstrate the effectiveness (or lack thereof) for various diagnostic and therapeutic interventions. The objective of this Spine Focus issue is not to replicate previous work in this area. Rather, our expert panel has chosen a set of potentially controversial topics for more in-depth study and discussion. A recurring theme is that chronic LBP is a heterogeneous condition, and this affects the way it is diagnosed, classified, treated, and studied. The efficacy of some treatments may be appreciated only through a better understanding of heterogeneity of treatment effects (i.e., identification of clinically relevant subgroups with differing responses to the same treatment). Current clinical guidelines and payer policies for LBP are systematically compared for consistency and quality. Novel approaches for data gathering, such as national spine registries, may offer a preferable approach to gain meaningful data and direct us towards a “results-based medicine.” This approach would require more high-quality studies, more consistent recording for various phenotypes and exploration of studies on genetic epidemiologic undertones to guide us in the emerging era of “results based medicine.”

Pathophysiology and natural history of cervical spondylotic myelopathy.

Study Design. This study is a combination of narrative and systematic review. Objective. Clinicians who deal with cervical spondylotic myelopathy (CSM) should be up-to-date with the emerging knowledge related to the cascade of pathobiological secondary events that take place under chronic cervical spinal cord compression. Moreover, by performing a systematic review, we aim to (1) describe the natural history and (2) determine potential risk factors that affect the progression of CSM. Summary of Background Data. The pathophysiology, natural history, as well as the factors associated with clinical deterioration have not been fully described in CSM. Methods. For the first part of the study, a literature review was performed. To answer key questions 1 and 2 of the second goal, a systematic search was conducted in PubMed and the Cochrane Collaboration Library for articles published between January 1, 1956, and November 7, 2012. We included all articles that described the progression and outcomes of CSM for which no surgical intervention was given. Results. By performing a narrative literature review, we found that the assumption that acute traumatic spinal cord injury and CSM share a similar series of cellular and molecular secondary injury events was made in the past. However, recent advances in basic research have shown that the chronic mechanical compression results in secondary injury mechanisms that have distinct characteristics regarding the nature and the temporal profile compared with those of spinal cord injury. For the purpose of the systematic review, 10 studies yielding 16 publications met inclusion criteria for key questions 2 and 3. Moderate-strength evidence related to the natural history of CSM suggests that 20% to 60% of patients will deteriorate neurologically over time without surgical intervention. Finally, there is low-strength evidence indicating that the area of circumferential compression is associated with deteriorating neurological symptoms. Conclusion. CSM has unique pathobiological mechanisms that mainly remain unexplored. Although the natural history of CSM can be mixed, surgical intervention eliminates the chances of the neurological deterioration. Evidence-Based Clinical Recommendations. Recommendation. Evidence concerning the natural history of CSM suggests that 20% to 60% of patients will deteriorate neurologically over time without surgical intervention. Therefore, we recommend that patients with mild CSM be counseled regarding the natural history of CSM and have the option of surgical decompression explained. Overall Strength of Evidence. Moderate Strength of Recommendation. Strong Summary Statements. Chronic compression of the spinal cord results in progressive neural cell loss related to secondary mechanisms including apoptosis, neuroinflammation, and vascular disruption.

The evidence for intraoperative neurophysiological monitoring in spine surgery: Does it make a difference?

Objective. The objective of this article was to undertake a systematic review of the literature to determine whether IOM is able to sensitively and specifically detect intraoperative neurologic injury during spine surgery and to assess whether IOM results in improved outcomes for patients during these procedures. Summary and Background Data. Although relatively uncommon, perioperative neurologic injury, in particular spinal cord injury, is one of the most feared complications of spinal surgery. Intraoperative neuromonitoring (IOM) has been proposed as a method which could reduce perioperative neurologic complications after spine surgery. Methods. A systematic review of the English language literature was undertaken for articles published between 1990 and March 2009. MEDLINE, EMBASE, and Cochrane Collaborative Library databases were searched, as were the reference lists of published articles examining the use of IOM in spine surgery. Two independent reviewers assessed the level of evidence quality using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) criteria, and disagreements were resolved by consensus. Results. A total of 103 articles were initially screened and 32 ultimately met the predetermined inclusion criteria. We determined that there is a high level of evidence that multimodal IOM is sensitive and specific for detecting intraoperative neurologic injury during spine surgery. There is a low level of evidence that IOM reduces the rate of new or worsened perioperative neurologic deficits. There is very low evidence that an intraoperative response to a neuromonitoring alert reduces the rate of perioperative neurologic deterioration. Conclusion. Based on strong evidence that multimodality intraoperative neuromonitoring (MIOM) is sensitive and specific for detecting intraoperative neurologic injury during spine surgery, it is recommended that the use of MIOM be considered in spine surgery where the spinal cord or nerve roots are deemed to be at risk, including procedures involving deformity correction and procedures that require the placement of instrumentation. There is a need to develop evidence-based protocols to deal with intraoperative changes in MIOM and to validate these prospectively.

Blood Loss in Major Spine Surgery : Are There Effective Measures to Decrease Massive Hemorrhage in Major Spine Fusion Surgery?

Study Design. Systematic review. Objective. To determine the definition and incidence of significant hemorrhage in adult spine fusion surgery, and to assess whether measures to decrease hemorrhage are effective. Summary of Background Data. Significant hemorrhage and associated comorbidities in spine fusion surgery have not yet been clearly identified. Several preoperative and intraoperative techniques are currently available to reduce blood loss and transfusion requirements such as cell saver (CS), recombinant factor VIIa, and perioperative antifibrinolytic agents, such as aprotinin, tranexamic acid, and &egr;-aminocaproic acid. Their effectiveness and safety in spine surgery is uncertain. Methods. A systematic review of the English-language literature was undertaken for articles published between January 1990 and April 2009. Electronic databases and reference lists of key articles were searched to identify published studies examining blood loss in major spine surgery. Two independent reviewers assessed the quality of the literature using the Grading of Recommendations Assessment, Development, and Evaluation criteria. Disagreements were resolved by consensus. Results. A total of 90 articles were initially screened, and 17 ultimately met the predetermined inclusion criteria. No studies were found that attempted to define significant hemorrhage in adult spine surgery. We found that there is a high level of evidence that antifibrinolytic agents reduce blood loss and the need of transfusion in adult spine surgery; however, the safety profile of these agents is unclear. There is very low evidence to support the use of CS, recombinant factor VIIa, activated growth factor platelet gel, or normovolemic hemodilution as a method to prevent massive hemorrhage in spine fusion surgery. Conclusion. There is no consensus definition of significant hemorrhage in adult spine fusion surgery. However, definition in the anesthesiology literature of massive blood loss is somewhat arbitrary but is commonly accepted to entail loss of 1 volume of the patients total blood (60 mL/kg in adults) in <24 hours. On the basis of the current literature, there is little support for routine use of CS during elective spinal surgery. Concerns related to the use of aprotinin were such that our panel of experts unanimously recommended against its use in spine surgery on the basis of the reports of increased complications. With respect to the antifibrinolytics of the lysine analog class (tranexamic acid and aminocaproic acid), on the basis of the available efficacy and safety data, we recommend that they be considered as possible agents to help reduce major hemorrhage in adult spine surgery.

Postoperative dysphagia in anterior cervical spine surgery

Study Design. Systematic review. Objective. To determine the incidence and prevalence and identify effective recommendations to minimize the incidence and prevalence of postoperative dysphagia after anterior cervical surgery. Summary of Background Data. The reported incidence and prevalence of postoperative dysphagia and risk factors associated with its development varies widely in the literature. Methods. A systematic review of the English-language literature was undertaken for articles published between January 1990 and December 2008. Electronic databases and reference lists of key articles were searched to identify published studies examining the incidence and prevalence of dysphagia after anterior cervical spine surgery. Two independent reviewers assessed the strength of literature using the Grading of Recommendations Assessment, Development, and Evaluation criteria, assessing quality, quantity, and consistency of results. Disagreements were resolved by consensus. Results. A total of 126 articles were initially screened, and 17 ultimately met the predetermined inclusion criteria. The rates of dysphagia found in the literature varied widely. Rates declined after surgery, but plateau at 1 year at a range of 13% to 21%. Risk factors identified were multilevel surgery and female sex. Specific preventive measures were not identified. Conclusion. A better understanding of dysphagia will require the development of better outcome measures.

Loss to follow-up.

In this issue, we answer three questions with respect to loss to follow-up in a clinical trial: How important is loss to follow-up? How is loss to follow-up calculated? How many patients can be lost to follow-up without mistrusting the results? 1. How important is loss to follow-up? The simple answer to this question is “very important” because loss to follow-up can severely compromise a studys validity. Incomplete follow-up biases the results when either: The dropout rates are different between study groups; or The patients who drop out are different from those who do not drop out. Why do these situations make a difference? Because in each situation, those lost to follow-up often have a different prognosis than those who complete the study. For example, patients who receive treatment for cervical myelopathy may not return for follow-up because they became asymptomatic and felt no need to return to see the surgeon. Conversely, some patients may not return because they had a particularly bad outcome (worse pain or function) or complication, or because they died. In either case, bias can affect the validity of the inferences drawn from the study. 2. How is loss to follow-up calculated? There is much confusion about how to determine the proportion of patients lost to follow-up. In order to correctly calculate the follow-up rate, one needs to know the denominator. In a randomized controlled trial (RCT), the denominator for each group is the number of patients who were randomized, not the number who received the treatment. For example, suppose we have an RCT comparing two treatment groups, Group A and Group B. The investigators evaluate 178 patients and randomize 120; 61 to Group A and 59 to Group B (Fig 1). Following the figure, we note that 49 patients received treatment A and 52 received treatment B. At the final follow-up 40 were analyzed in Group A and 41 in Group B. How many were considered lost to follow-up? Many would consider the loss to follow-up rate to be 9 (18%) of 49 in treatment A and 11 (21%) of 52 in treatment B using as the denominator only those that were treated. However, the real proportion lost to follow-up must consider those who were randomly assigned, even if they did not receive treatment. In the present example, this is calculated as 21 (34%) of 61 for treatment A and 18 (31%) of 59 for treatment B. Fig 1 Hypothetical example of patients lost to follow-up in a randomized controlled trial. When calculating loss to follow-up in a retrospective cohort study, all individuals receiving treatment during the study period should be used as the denominator, not just those with complete data. For example, lets say you want to compare decompression plus lumbar fusion with decompression alone in disc herniation and the data available are all patients receiving either treatment in the last 5 years (N = 275). However, the database from which the data are obtained is incomplete and only 190 have the necessary data available. Since the investigators stated as part of the inclusion criteria that only those patients with complete data are included, they consider the follow-up to be 100% (190/190). This conclusion is wrong. The denominator should include all patients who underwent the surgery irrespective of completeness of data. The follow-up rate for this example is 69% (190/275). 3. How many patients can be lost to follow-up without mistrusting the results? Some have suggested that 20% poses serious threats to validity 1. This may be a good rule of thumb, but keep in mind that even small proportions of patients lost to follow-up can cause significant bias 2. One way to determine if loss to follow-up can seriously affect results is to assume a worst-case scenario with the missing data and look to see if the results would change. Here is an example: Lets assume a multicenter study enrolled 500 patients into each arm of a study comparing artificial disc replacement (ADR) with fusion, and the end point is adjacent segment disease (ASD). The trial numbers are found in Fig 2. Fig 2 Hypothetical example of the effect of loss to follow-up considering a worst-case scenario. ADR indicates artificial disc replacement; ASD, adjacent segment disease. The proportion of patients with ASD in the ADR group is half as much versus the fusion group, 25% (100/400) compared with 50% (200/400). If we assume that the 100 lost to follow-up in the ADR group had ASD and the 100 lost to follow-up in the fusion group did not, then the rate of ASD in each group would be 40% (200/500). In this case, adopting the worst-case scenario for the intervention group with respect to those lost to follow-up causes the results to change significantly from half the rate of ASD with ADR to the same rate. When this happens, loss to follow-up can threaten the internal validity of the trial. Only when the worst case does not change the inferences derived from the results is lost to follow-up not a problem.

The role of classification of chronic low back pain.

Study Design. Systematic review. Objective. To describe the various ways chronic low back pain (CLBP) is classified, to determine if the classification systems are reliable and to assess whether classification-specific interventions have been shown to be effective in treating CLBP. Summary of Background Data. A classification system by which individual patients with CLBP could be identified and directed to an effective treatment protocol would be beneficial. Those systems that direct treatment have the greatest potential influence on patient outcomes. Methods. A systematic search was conducted in MEDLINE and the Cochrane Collaboration Library for English language literature published through January 2011. We included articles that specifically described a clinical classification system for CLBP, reported on the reliability of a classification system, or evaluated the effectiveness of classification-specific interventions. Results. A total of 60 articles were initially reviewed. We identified 28 classification systems that met inclusion criteria: 16 diagnostic systems, 7 prognostic systems, and 5 treatment-based systems. In addition, we found 10 randomized controlled trials of CLBP treatment from which we compared inclusion and exclusion criteria. Treatment-based systems were all directed at nonoperative management. Four of the 5 treatment-based systems underwent reliability testing and were found to have interobserver agreement of 70% to 100%. Reliability increased with training and familiarity with a given classification. As the number of subgroups within a classification increased, interobserver agreement decreased. Function and pain were similar between patients treated with the McKenzie classification system and those treated with dynamic strengthening training after 8 months of follow-up in one randomized controlled trial. One prospective cohort study reported better pain and function using the Canadian Back Institute Classification system than with standard rehabilitation. An analysis of the admission criteria to recent randomized studies with either nonoperative care or another surgical intervention provided a methodology for refining criteria to be met by patients considering surgery. Conclusion. There currently are many classification systems for CLBP; some that are descriptive, some prognostic, and some that attempt to direct treatment. We recommend that no one classification system be adopted for all purposes. We further recommend that future efforts in developing a classification system focus on one that helps to direct both surgical and nonsurgical treatments. Clinical Recommendations. There currently are many classification systems for CLBP; some that are descriptive, some prognostic, and some that attempt to direct treatment. We recommend that no one classification system be adopted for all purposes. We further recommend that future efforts in developing a classification system focus on one that helps to direct both surgical and nonsurgical treatments.

Anticoagulation risk in spine surgery.

Study Design. Systematic review. Objective. To determine the high-risk populations for thromboembolic events in spine surgery patients, the risk of anticoagulation in spine surgery patients by type of anticoagulation, and whether there is a safe perioperative window of nonanticoagulation for these high-risk patients. Summary of Background Data. Thromboembolic complications after major spinal surgery is a significant risk for patients. Anticoagulation to reduce this risk is of concern because of the possibility of excessive bleeding or postoperative hematomas and associated neurologic deficits. There seems to be a paucity of literature on this topic. Methods. A systematic review of the English-language literature was undertaken for articles published between January 1990 and December 2008. Electronic databases and reference lists of key articles were searched to identify published studies examining coagulopathy in major spine surgery. Two independent reviewers assessed the strength of literature using the Grading of Recommendations Assessment, Development, and Evaluation criteria, assessing quality, quantity, and consistency of results. Disagreements were resolved by consensus. Results. A total of 93 articles were initially screened, and 29 ultimately met the predetermined inclusion criteria. The risk of thromboembolism in patients not receiving chemical prophylaxis was slightly higher in surgery to correct deformity (5.3%) and trauma patients (6.0%) than in surgery for degenerative conditions (2.3%). Fatal pulmonary embolism was rare. Bleeding complications occurred rarely with the use of anticoagulation; risk of major bleeding ranged from 0.0% to 4.3% across several types of anticoagulants. Postoperative hematoma was reported in only 10 of 2507 patients. Conclusion. Venous thromboembolism is uncommon after elective spine surgery. Trauma patients are at increased risk, and chemical prophylaxis should be considered. The safe timing of the administration of anticoagulation agents is unknown.